Chromecast Ultra + LG 2016 OLED Playing Dolby Vision at 1080p24 instead of 4K24

[home_theatre_man]

I just noticed that my Chromecast Ultra is no longer sending 4K Dolby Vision at 24 Hz to my 2016 LG OLED for VUDU UHD titles. The signal is being sent as 1080p Dolby Vision at 24 Hz. 4K has been working for a LONG time; is this a new bug in someone's firmware?

Anyone else notice this? Can we please get this fixed ASAP?

Netflix is doing the same thing, so I'm guessing a Google build has broken it.

[Jake]

Check out this Google FAQ - I think this is a new Chromecast Ultra "feature":

https://support.google.com/chromecas.../7186055?hl=en

2016 LG TVs do not support 4k@60Hz for Dolby Vision input. On the other hand, I believe 4K@24Hz DV support was added by LG a while ago, and the CCU previously used it. Hopefully they didn't break 4K@24Hz support with this feature. (4K@30Hz does look jittery because it's converting native FPS of 24 -> 30).

[home_theatre_man]

Check out this Google FAQ - I think this is a new Chromecast Ultra "feature":

https://support.google.com/chromecas.../7186055?hl=en

2016 LG TVs do not support 4k@60Hz for Dolby Vision input. On the other hand, I believe 4K@24Hz DV support was added by LG a while ago, and the CCU previously used it. Hopefully they didn't break 4K@24Hz support with this feature. (4K@30Hz does look jittery because it's converting native FPS of 24 -> 30).

The CCU has had the Video Smoothness feature for some time, and I have periodically tested it both on and off in conjunction with the 2016 LG OLED through various firmware builds on both devices. Despite what Google's description would indicate, there has never been any difference in the resolution or frame rate output by the CCU for any apps I use, including Netflix and VUDU, based on the Video Smoothness setting.

Until last week, the CCU was sending VUDU UHD to the LG as Dolby Vision 4K@24Hz, just as you describe. Again, it did this with Video Smoothness turned on or off - didn't matter. Saturday night, I played a VUDU UHD title and was surprised to find the format being sent by the CCU was Dolby Vision 1080p@24Hz instead of 4K@24Hz. I tried Video Smoothness on and off, but it did not have an effect either way. I tried a number of different configurations and troubleshooting steps, including resetting the CCU.

Subsequent to my first post, I have observed that VUDU HDX format is now being output by the CCU at 1080p@24Hz instead of upscaled to 4K@60Hz as it has been since I started using the CCU. (The CCU outputs almost everything at 4K@60Hz unless there is an incompatibility in the display - like with Dolby Vision.) Netflix 4K SDR and Dolby Vision are also being output at 1080p, where previously the CCU output was 4K.

Movies Anywhere and Google Play are correctly sending 4K@60 HDR-10 (display supports 4K HDR-10 @ 60Hz).

It appears to me that Google changed something in the CCU that altered the way it handles Dolby Vision for displays that don't support 4K@60Hz. As far as I can tell, only the two providers who were taking advantage of the 4K@24Hz Dolby Vision output (Netflix and VUDU) were affected. What's odd to me is that the change doesn't appear to be related to frame rate, as the CCU is still outputting 24 Hz - just 1080p instead of 4K. So it can't really be argued that they wanted to step back to 1080p so they could output 60Hz instead of 24Hz. If the output was now 60Hz, I could believe that was maybe an intentional change. But sticking with 24Hz and rolling back to 1080p? I have to believe that's a bug.

UPDATE: Upon further testing, the issue with 1080p@24Hz output of HDX, etc., occurs after the initial switch to 1080p@24Hz when watching Dolby Vision. That is, if you watch HDX first you'll get 4K@60Hz for HDX. Watch UHD (Dolby Vision) first, and you'll get 1080p@24Hz for HDX. Ending/resuming the cast from VUDU or casting from another app and then returning to VUDU "resets" the output back to 4K@60Hz.

[Jake]

Thanks for the info, we will try to reproduce in the office and report it to Google.

[home_theatre_man]

No problem. Feel free to reach out if you have any questions/need additional details.

[SinGA]

I'm having the same problem.

[SinGA]

Jake I opened a case with Chromecast support over this issue. I hope you were able to report it to them as well. I know its not just Vudu that's affected, but since Vudu has almost everything in Dolby Vision, I am unable to watch my movies in 4k right now.

[SinGA]

would love an update on this issue!

[Jake]

would love an update on this issue!

I know Google is aware of the issue and looking into it. Don't have any more details, but I assume a fix would involve an eventual firmware update.

[SinGA]

I know Google is aware of the issue and looking into it. Don't have any more details, but I assume a fix would involve an eventual firmware update.

THANK YOU!

[home_theatre_man]

As of this date, the issue is still occurring. My CCU is in the preview program, and there has not been an update as of yet. Fingers crossed, as I am in the same boat being unable to watch my VUDU library in 4K with Dolby Atmos audio.

[SinGA]

Thanks for the update "man"! I have also been hounding Google for an update but their Chromecast support is a bit of a mess.

[SinGA]

The latest from Google CCU support:

"Upon checking the current firmware version of your Google Chromecast Ultras is the most updated one. Which is may no longer compatible with the software of your TV. That's is why you are experiencing this issue, can you check with LG if they have upcoming software update available for your TV. Since the current firmware version on your Chromecast Utlra is compatible to almost every 4k TV that was recently release.

I suggest, try using the Chromecast Ultra on a different 4k TV just for us to isolate the issue. Regarding your question on reversing the update, I'm afraid we can't undo the update. "

So what they are saying is we are SOL and this will be broken forever for all 2016 LG owners.

[SinGA]

"Your Chromecast Ultra does not support a 4k video running on 24Hz. The minimum that it can support are 4k video running on 50Hz and 60Hz that is the main reason why you are having issue playing a 4k video. "

and

"Google Chromecast Ultra does not support 24Hz, most likely the reason you were able to play a 4k video under 24Hz before was most likely your TV was able to adapt and overide the 24Hz and adapt to Chromecast video codecs. "

[Epedemic]

These new statements from Google are complete nonsense, as 4K+DV+24hz have been working from 2016 until now on the exact same hardware combination. Also the LG 2016 TV's have not recieved FW updates in ages to change this. Google is to blame, with some software crap they implemented in recent firmwares. Of course they should not roll back firmwares on our Chromecasts, but they should roll back the specific changes THEY made to that part of the firmware in the next release....

Also funny that they have always claimed that the CCU does not support 24hz, when the current situation gives us 1080p+DV in... you guessed it: 24hz

They should come around once the issue gets the attention of an actual competent sw engineer who knows his stuff and actually understand what we mean.